We have shown by recording electrophysiologically from the olfactory surface that odorants can be classified according to the spatial focus of their ability to excite olfactory receptors in the tiger salamander. To elucidate further the inherent topographical organization of the olfactory epithelium, we plan: (1) to increase the number of odorants tested; and (2) to define specific odor maps in sufficient detail to allow a more comprehensive analysis of their characteristics. From such an approach we hope to establish the extent to which different odorants elicit different maps of excitation on the olfactory epithelium.